Merge pull request #16 from tuxcrafting/fix-dhcp-pedanticness

Fix dependence on DNS and ROUTER messages during DHCP request

README.md

@@ -20,7 +20,7 @@ Software included in Shrine:
 Setting up with networking
 ==========================
 - Native Stack (highly experimental)
-  - configure your VM networking: *Adapter Type: PCnet-PCI II* (`pcnet` in QEMU)
+  - configure your VM networking: *Adapter Type: PCnet-PCI II* (QEMU: `-netdev user,id=u1 -device pcnet,netdev=u1`)
   - *Attached to: NAT* seems to be the most reliable setting, Bridged Mode also works somewhat
   - On boot, Shrine will automatically attempt to acquire an IP address. If you don't get a message about "Configuring network", the adapter was not detected.
 

SnailNet/Dhcp.HC

@@ -242,7 +242,7 @@ I64 DhcpParseOffer(U32 xid, U8* data, I64 length, U32* yiaddr_out,
 
   //"DhcpParseOffer: end %d %d %d %d\n", have_type, have_dns, have_subnet, have_router;
 
-  if (have_type && have_dns && have_subnet && have_router) {
+  if (have_type && have_subnet) {
     *yiaddr_out = ntohl(hdr->yiaddr);
     return 0;
   }

SnailNet/IPv4.HC

@@ -86,6 +86,11 @@ static I64 GetEthernetAddressForIP(U32 ip, U8** mac_out) {
   }
   // outside this subnet; needs routing
   else if ((ip & ipv4_subnet_mask) != (my_ip & ipv4_subnet_mask)) {
+    // no gateway
+    if (ipv4_router_addr == 0) {
+      return IPV4_EADDR_INVALID;
+    }
+
     // FIXME: infinite loop if mis-configured
 
     return GetEthernetAddressForIP(ipv4_router_addr, mac_out);